Scanning devices have traditionally been used for a variety of purposes. For example, scanning devices can be used to measure the distance to a particular object, and to detect the presence of an object located within the scanning area. Scanning devices can also be used as an integral part of an electronic component, and can monitor a known environment to detect and measure changes to that environment. The potential uses for scanning devices is virtually unlimited.
Many different scanners, particularly laser scanners, have been developed in recent times. Many scanners are capable, however, of scanning only in a single plane. Where scanning is done in multiple dimensions, multiple drive mechanisms or motors (e.g., a rotational drive motor and a vertical tilt motor) are used to project the beam of laser light in various directions.
One particular need for a suitable scanning device exists with respect to measuring plant and forest canopies. The biomass production of plants is proportional to the radiation from the sun absorbed by the plant leaves. Measuring the density of a plant canopy will provide information with respect to how much light a canopy intercepts. Use of a scanning device to measure the canopy enables statistical data to be generated and compiled to determine optimal spacing of plants, optimal thinning of timber, soil erosion effects, and many other aspects that affect the environment surrounding plant growth.
A few rudimentary types of canopy measuring methods are known. One prior method of measuring a plant canopy involves inserting a rod through a plant canopy and determining if it strikes any leaves. This method of measuring provides at least some type of data by which the probability of hitting the plant canopy could be determined. Another known method involves placing an array of photodiodes on the ground under the plant growth to detect the amount of sun light which passes through the canopy, somewhat similar to the rod described above. With each of these methods, the plant canopy is determined by an inversion calculation of penetration by the rod or sun light through the plant canopy. No direct measurements of the plant canopy are taken. Still another method involves using a manual, linear laser detector to detect and measure plants from the location of the operator.
The foregoing methods have several drawbacks and disadvantages. Among others, they are difficult to implement, imprecise, and do not allow sufficient, reliable data to be obtained to make an accurate determination as to the plant canopy.
There exists a need, therefore, to develop a scanning device for all around use that can directly measure and detect objects in an area immediately surrounding the scanning device. There is also a need to develop a lightweight, portable scanning device capable making extremely fast and accurate direct measurements of objects, particularly plant and forest canopies.
The present invention involves a laser scanning apparatus which can be used in a variety of applications to directly measure and detect objects surrounding the scanning apparatus. The laser scanning apparatus is portable and particularly suited for scanning a plant canopy. The various objects, features, and advantages of the invention will become apparent from the detailed disclosure which follows.